cluster: fix the issue when endpoints are empty in scale-out

[9547]

What problem does this PR solve?

Fix #1226

What is changed and how it works?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Code changes

• Has exported function/method change
• Has exported variable/fields change
• Has interface methods change
• Has persistent data change

Side effects

• Possible performance regression
• Increased code complexity
• Breaking backward compatibility

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation

Release notes:

NONE

[9547]

/cc @lucklove

PTAL

[codecov-io]

Codecov Report

Merging #1227 (1882f4f) into master (ede1182) will increase coverage by 12.04%.
The diff coverage is 33.33%.

❗ Current head 1882f4f differs from pull request most recent head a4b8449. Consider uploading reports for the commit a4b8449 to get more accurate results

@@             Coverage Diff             @@
##           master    #1227       +/-   ##
===========================================
+ Coverage   26.27%   38.31%   +12.04%     
===========================================
  Files         263      224       -39     
  Lines       18684    16297     -2387     
===========================================
+ Hits         4909     6245     +1336     
+ Misses      13022     8926     -4096     
- Partials      753     1126      +373     

Flag	Coverage Δ
cluster	38.31% <33.33%> (?)
integrate	38.31% <33.33%> (+21.80%)	⬆️
tiup	?
unittest	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pkg/cluster/api/pdapi.go	44.28% <0.00%> (+44.28%)	⬆️
pkg/cluster/ctxt/context.go	89.09% <ø> (+89.09%)	⬆️
pkg/cluster/manager/scale_out.go	0.00% <0.00%> (-11.77%)	⬇️
pkg/cluster/operation/action.go	57.14% <0.00%> (ø)
pkg/cluster/spec/instance.go	63.51% <ø> (+44.59%)	⬆️
pkg/cluster/spec/tiflash.go	52.63% <50.00%> (-0.06%)	⬇️
pkg/repository/store/store.go	0.00% <0.00%> (-100.00%)	⬇️
pkg/repository/utils/hash.go	0.00% <0.00%> (-81.82%)	⬇️
pkg/meta/err.go	0.00% <0.00%> (-81.25%)	⬇️
pkg/telemetry/meta.go	0.00% <0.00%> (-80.00%)	⬇️
... and 241 more

---

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[9547]

@AstroProfundis @lucklove PTAL

[lucklove]

/lgtm

[ti-chi-bot]

[REVIEW NOTIFICATION]

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• lucklove

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[lucklove]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Details

Commit hash: a4b8449

[ti-chi-bot]

@9547: Your PR was out of date, I have automatically updated it for you.

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